There have been numerous clamping devices which describe means of holding a workpiece. The following U.S. patents have been issued to the applicant.
______________________________________ U.S. Pat. No. ISSUE DATE ______________________________________ 4,632,375 12/30/86 4,648,555 03/10/87 4,717,132 01/05/88 4,732,373 03/22/88 4,763,887 08/16/88 4,767,110 08/30/88 4,807,863 02/28/89. ______________________________________
The previous U.S. patent application Ser. No. 743,981 (U.S. Pat. No. 4,732,373, after being put into practice for quantity production, was found to have defects existing between its rotary and sliding clamping members and the socket base of the jaw. These included the connection of the pin in the socket base and the rotary and sliding clamping member. The connection between them is poor and it is difficult to control the quality. This has affected the rotating action and has resulted in the production process being complex. In order to solve the said defects effectively, the applicant has made the following improvements.